test.ts

export class AppComponent implements OnInit {

  // public array of DocumentData
  public documentList: DocumentData[] = [];
  public selectedDocument: DocumentData | undefined;
  
  constructor(private http: HttpClient) {}

  ngOnInit() {
    this.getFilenames();
  }

  getFilenames() {
    this.http.get<DocumentData[]>('/document/list').subscribe(
      (result) => {
        this.documentList = result;
      },
      (error) => {
        console.error(error);
      }
    );
  }
}